Field grain losses and insect pest management practices in subsistence agriculture: Farmers' perceptions

A farm survey was conducted in subsistence farming communities to document the major grain crops, insect pests, indigenous pest control methods (PCM) and farmer perceptions of grain losses associated with identifiable pest species and perceived efficacies of the PCMs. Maize, beans and sorghum were identified as the major staple food crops, with the major pests being cutworm, stem borers, aphids, beanfly, pod borers, armyworms and termites. Statistical analyses revealed that the level of crop yield losses was dependent upon the area cropped, total yield and respondents' background. There was, however, a negative correlation between crop yield loss due to insect pests and the efficacy of PCM applied. Farmers lost, on average, 24.75% of their crop to insect pests with high value crops suffering the greatest insect pest attack in terms of species diversity and magnitude of damage incurred. The occurrence of field insect pests varied from season to season with most species reportedly occurring during the long rains. Most (72.6%) farmers never applied any PCM against all the insect pests of food crops. The use of synthetic pesticides and alternatives accounted for less than 10%. Seventy one percent of the respondents crops, with the major pests being cutworm, stem borers, aphids, beanfly, pod borers, armyworms and termites. Statistical analyses revealed that the level of crop yield losses was dependent upon the area cropped, total yield and respondents' background. There was, however, a negative correlation between crop yield loss due to insect pests and the efficacy of PCM applied. Farmers lost, on average, 24.75% of their crop to insect pests with high value crops suffering the greatest insect pest attack in terms of species diversity and magnitude of damage incurred. The occurrence of field insect pests varied from season to season with most species reportedly occurring during the long rains. Most (72.6%) farmers never applied any PCM against all the insect pests of food crops. The use of synthetic pesticides and alternatives accounted for less than 10%. Seventy one percent of the respondents reported that the efficacy of the PCMs applied was unknown. Some of the indigenous PCMs reportedly used included crude powders and aqueous extracts of local botanical plants such as Tobacco, Tephrosia, and Basil. The study recommends that bioassay-guided investigations be instituted to develop and rationalise the use of identified PCM strategies compatible with the target user domains.Keywords: Farmer perceptions yield loss, indigenous pest control Journal of Agriculture, Science and Technology Vol. 8 (1) 2006: pp. 24-4

Effect of intercropping maize and soybeans on Striga hermonthica parasitism and yield of maize

Striga hermonthica a major biotic constraint to cereal production can be controlled by trap crops. Soybean cultivars vary in ability to stimulate suicidal germination of the weed. An experiment was conducted to select soybean (Glycine max) varieties with the ability to stimulate germination of S. hermonthica seeds. Experiments were conducted with strigol Nijmegen 1® (GR 24), a synthetic stimulant, as a check. In the pot and field experiments, maize (variety WH507) was intercropped with soybeans. Variation occurred among soybean varieties in inducing germination of S. hermonthica. The relative germination induction by soybean varieties ranged from 8% to 66% compared to 70% for synthetic stimulant check. Varieties TGX1448-2E, Tgm 1576, TGX1876-4E and Tgm 1039 had the highest relative germination. Soybean varieties TGX 1831-32E, Tgm944, Tgm 1419 and Namsoy4m had high stimulation but low attachment. Intercropping maize with soybeans in the field led to a low S. hermonthica count and high maize yield

Effect of ten-valent pneumococcal conjugate vaccine on invasive pneumococcal disease and nasopharyngeal carriage in Kenya: a longitudinal surveillance study

BACKGROUND: Ten-valent pneumococcal conjugate vaccine (PCV10), delivered at 6, 10, and 14 weeks of age was introduced in Kenya in January, 2011, accompanied by a catch-up campaign in Kilifi County for children aged younger than 5 years. Coverage with at least two PCV10 doses in children aged 2-11 months was 80% in 2011 and 84% in 2016; coverage with at least one dose in children aged 12-59 months was 66% in 2011 and 87% in 2016. We aimed to assess PCV10 effect against nasopharyngeal carriage and invasive pneumococcal disease (IPD) in children and adults in Kilifi County. METHODS: This study was done at the KEMRI-Wellcome Trust Research Programme among residents of the Kilifi Health and Demographic Surveillance System, a rural community on the Kenyan coast covering an area of 891 km2. We linked clinical and microbiological surveillance for IPD among admissions of all ages at Kilifi County Hospital, Kenya, which serves the community, to the Kilifi Health and Demographic Surveillance System from 1999 to 2016. We calculated the incidence rate ratio (IRR) comparing the prevaccine (Jan 1, 1999-Dec 31, 2010) and postvaccine (Jan 1, 2012-Dec 31, 2016) eras, adjusted for confounding, and reported percentage reduction in IPD as 1 minus IRR. Annual cross-sectional surveys of nasopharyngeal carriage were done from 2009 to 2016. FINDINGS: Surveillance identified 667 cases of IPD in 3 211 403 person-years of observation. Yearly IPD incidence in children younger than 5 years reduced sharply in 2011 following vaccine introduction and remained low (PCV10-type IPD: 60·8 cases per 100 000 in the prevaccine era vs 3·2 per 100 000 in the postvaccine era [adjusted IRR 0·08, 95% CI 0·03-0·22]; IPD caused by any serotype: 81·6 per 100 000 vs 15·3 per 100 000 [0·32, 0·17-0·60]). PCV10-type IPD also declined in the post-vaccination era in unvaccinated age groups (<2 months [no cases in the postvaccine era], 5-14 years [adjusted IRR 0·26, 95% CI 0·11-0·59], and ≥15 years [0·19, 0·07-0·51]). Incidence of non-PCV10-type IPD did not differ between eras. In children younger than 5 years, PCV10-type carriage declined between eras (age-standardised adjusted prevalence ratio 0·26, 95% CI 0·19-0·35) and non-PCV10-type carriage increased (1·71, 1·47-1·99). INTERPRETATION: Introduction of PCV10 in Kenya, accompanied by a catch-up campaign, resulted in a substantial reduction in PCV10-type IPD in children and adults without significant replacement disease. Although the catch-up campaign is likely to have brought forward the benefits by several years, the study suggests that routine infant PCV10 immunisation programmes will provide substantial direct and indirect protection in low-income settings in tropical Africa. FUNDING: Gavi, The Vaccine Alliance and The Wellcome Trust of Great Britain